This will be an an Multiverse book, 

First few chaps will be introduction and then ML will travel to his first world, it will be One Piece, and it will be long journey , around 80 chaps approx., 

So, It is Marvel but not from start, first few chaps will be marvel then One piece long journey, and then a long marvel and then another long another world.

I will add Volume name based on the worlds.

It will be Harem : 5 to 6 girls, (per world)

funny and caring ML,